class_docstr: This plan used to store metadata to perform function table scan.
  
  Arguments:
      func_expr(FunctionExpression): parameterized function expression that
          reference columns from a table expression that precedes it.
      do_unnest(bool): if True perform unnest operation on the output of FunctionScan
code: def func_expr(self):
      return self._func_expr
  
file_path: evadb/evadb/plan_nodes/function_scan_plan.py
imports: from evadb.expression.function_expression import FunctionExpression
  from evadb.plan_nodes.abstract_plan import AbstractPlan
  from evadb.plan_nodes.types import PlanOprType
label_desc: Use image node_id 2 for calling the FunctionScanPlan obj's underlying member method code with example usage: obj.func_expr() and returns: self